Validation of Simulated Material Flow in Aluminium Hot Extrusion with a Novel Visualisation Method

2014 ◽  
Vol 794-796 ◽  
pp. 15-20 ◽  
Author(s):  
Dieter Horwatitsch ◽  
Jonas Müller ◽  
Helmut Kilian ◽  
Martin Brandecker ◽  
Arne Wahlen
Keyword(s):  
Computer Tomography ◽  
Material Flow ◽  
Hot Extrusion ◽  
Flow Behaviour ◽  
Fe Model ◽  
Model Data ◽  
Physical Experiments ◽  
Simulated Material ◽  
Visualisation Method ◽  
Copper Mesh

Commonly used visualisation methods for observing material flow during extrusion are either labor intensive, prone to loss of the tracer pattern or subject to different flow behaviour than occurs in practice. A novel visualisation method using a copper mesh inlay and computer tomography was developed and used to visualise the flow behaviour of partially extruded EN AW-6082 aluminum billets. In parallel with the physical experiments, a finite element (FE) model was developed and compared with the experiments. The material flow was readily observable from the computer tomography images and the FE model data closely matched the experimental results.

Improved Sheet Bulk Metal Forming Processes by Local Adjustment of Tribological Properties

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
H. Hetzner ◽  
J. Koch ◽  
S. Tremmel ◽  
S. Wartzack ◽  
M. Merklein
Keyword(s):  
Contact Pressure ◽  
Metal Forming ◽  
Material Flow ◽  
System Analysis ◽  
Sheet Thickness ◽  
Fe Model ◽  
Forming Process ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Functional Features

This paper is focused on a combined deep drawing and extrusion process dedicated to the new process class of sheet bulk metal forming (SBMF). Exemplified by the forming of gearings, combined sheet and bulk forming operations are applied to sheet metal in order to form local functional features through an intended and controlled change of the sheet thickness. For investigations on the form filling and the identification of significant influencing factors on the material flow, a FE simulation model has been built. The FE model is validated by the results of manufacturing experiments using DC04 with a thickness of 2.0 mm as blank material. Due to the fact that the workpiece is in extensive contact to the tool surface and that the pressure reaches locally up to 2500 MPa, the tribological conditions are a determining factor of the process. Thus, their influence is discussed in detail in this paper. In the first instance, different frictional zones having a distinct effect on the resulting material flow are identified and their effect on improved form filling is demonstrated. Subsequently, a more comprehensive methodology is developed to define tribological zones of forming tools. For this, a system analysis of the digital mock-up of the forming process is performed. Besides friction, other relevant aspects of forming tool tribology like contact pressure, sliding velocity, and surface magnification are considered. The gathered information is employed to partition the tools into tribological zones. This is done by systematically intersecting and re-merging zones identified for each of the criterion. The so-called load-scanning test allows the investigation of the friction coefficient in dependence of the contact pressure and possible loading limits of tribological pairings. It provides an appropriate tribological model test to evaluate tribological measures like coatings, surface textures and lubricants with respect to their targeted application in particular zones. The obtained results can be employed in the layout of further forming processes to reach the desired process behavior. This can be, for example, an improved form filling, less abrasive wear and adhesive damage or lower forming forces, respectively tool load for an improved durability of the die.

Effect of Hot Extrusion on the Flow Behaviour of a Nickel-Based P/M Superalloy

2019 ◽  
Vol 298 ◽  
pp. 43-51
Author(s):  
Jia Yong Si ◽  
Song Hao Liu ◽  
Long Chen
Keyword(s):  
Activation Energy ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Work Hardening ◽  
Rate Sensitivity ◽  
Hot Extrusion ◽  
Turbine Disk ◽  
Flow Behaviour ◽  
Strain Rates ◽  
Work Hardening Rate

This research investigated the effect of hot extrusion on the flow behaviour of nickel-based superalloy FGH4096 by hot compression experiments in the temperature range from 1020 to 1110 °C and strain rates ranging from 0.1 to 0.001 s-1. The influence of the hot extrusion on the initial microstructures, work hardening rate, strain rate sensitivity, and activation energy of deformation were discussed. The results show that the extruded microstructure is constituted by the fine dynamic recrystallisation of grains. The true strain-true stress curves show that the as-HIPed and as-HEXed FGH4096 superalloy present double flow stress peaks and discontinuous flow softening. The as-HEXed FGH4096 is easily dynamically softened at high temperatures and high strain rates compared with as-HIPed microstructures. As for the work hardening rate, the as-HEXed FGH4096 exhibits higher θ values than that of as-HIPed. It is beneficial to the homogenous deformation and grain refinement during subsequent turbine disk forging. Comparing to as-HIPed FGH4096, the highest strain rate sensitivity value of as-HEXed is 0.306 at 1110 °C. The isothermal superplastic forging of a P/M turbine disk may be carried out at this temperature. The deformation activation energy value of the as-HIPed FGH4096 is lower which means that dislocation sliding and climbing can be easily initiated in the as-HIPed alloy.

Newest Developments on the Manufacture of Helical Profiles by Hot Extrusion

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Nooman Ben Khalifa ◽  
A. Erman Tekkaya
Keyword(s):  
Material Flow ◽  
Twist Angle ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Die Design ◽  
3D Fem ◽  
Extrusion Dies ◽  
Application Fields ◽  
Twisting Angle ◽  
Screw Rotors

A new innovative direct extrusion process, helical profile extrusion (HPE) is presented, which increases the flexibility of aluminum profile manufacturing processes. The application fields of such profiles can be seen in screw rotors for compressors and pumps. The investigations concentrate on experimental and numerical analyses by 3D-FEM simulations to analyze the influence of friction and the material flow on the twisting angle and contour accuracy. By means of finite-element method (FEM), the profile shape could be improved by modifying the die design. The numerical results were validated by experiments. For these investigations, a common aluminum alloy AA6060 was used. Mainly, the friction in the die influences the twist angle and the shape of the helical profile. Two die coatings were analyzed, but the friction was not substantially decreased in any of these cases. Although there is no efficient practical solution for reducing the friction in extrusion dies using tested die coatings, the required profile contour could be achieved by new die designing and by modifying the material flow. However, increasing the twist angle is limited due to geometrical aspects of this technology, namely, by the ratio of the volume to the contact area with the die for the displaced metal.

scholarly journals Electrically-assisted mechanical clinching of AA6061-T6 aluminum to galvanized DP590 steel: effect of geometrical features on material flow and mechanical strength

2020 ◽  
Vol 21 (5) ◽  
pp. 529
Author(s):  
Abozar Barimani-Varandi ◽  
Abdolhossein Jalali Aghchai
Keyword(s):  
Mechanical Strength ◽  
Material Flow ◽  
Failure Modes ◽  
High Strength ◽  
Fe Model ◽  
Electrically Assisted ◽  
Geometrical Features ◽  
Mechanical Clinching ◽  
Failure Loads ◽  
Joint Section

The mechanical clinching as an alternative joining process for fabricating lightweight aluminum to steel assemblies may face the challenges when joining low-ductility aluminum alloy to high-strength steel. Several researches have been focused on applying the electrically-assisted processes in various fields due to energy efficiency as well as practical simplicity, in order to improve the formability. This paper concentrates on the electrically-assisted mechanical clinching (EAMC) of AA6061-T6 aluminum to galvanized DP590 steel. To this end, a combination of experimental and numerical clinching tests was performed using extensible die at different penetration depths, in which controlling the material flow was obtained by applying newly defined chamfer ratio RC in order to guarantee the strong mechanical interlock. The joint section parameters, failure loads, and failure modes were measured. The effects of the geometrical features on material flow and mechanical strength of clinched joints were analyzed using a FE model. The results showed that the defined parameter RC greatly increased the strength with the use of the EAMC process, which came with a reduction in forming load.

Improving the Fatigue Resistance Of Cold Forging Tools by Fe Simulation and Computer Aided Die Shape Optimization

1992 ◽  
Vol 206 (2) ◽  
pp. 143-150 ◽  
Author(s):  
M Geiger ◽  
M Hänsel ◽  
T Rebhan
Keyword(s):  
Finite Element ◽  
Fatigue Resistance ◽  
Process Simulation ◽  
Material Flow ◽  
Cold Forging ◽  
Material Research ◽  
Fe Model ◽  
Tool Failure ◽  
Friction Forces ◽  
Computer Aided

It is the intention of the present article to point out a new method for computer aided tool optimization as part of computer integrated tool manufacturing. Based on the results of finite element (FE) analysis and subsequent tool failure simulation, it is possible to optimize the FE model of a tool already at the stage of construction, in order to enhance the service life and process reliability. The permissible degree of freedom for any shape correction, of course, is mainly limited by constructive constraints of the tool and the properties of the material flow during the extrusion process. Thus the resulting optimized geometry has to he considered as a possible constructive alternative. However, analytical as well as practical solutions already show that a parabolical or elliptical curved surface contour, replacing a regular radius, not only improves the fatigue resistance but may have a positive influence on material flow behaviour, friction forces and resulting tool loads as well (1). The influence imposed on the material flow by the geometrical modification of the die shape will be clarified in future by the results of FE process simulation. A renewed simulation run, employing the optimized shape, may be conducted immediately after the optimization process. Along with current material research, the simulation of tool failure based on the finite element method (FEM) analysis of forging techniques (FE process simulation) therefore represents a promising direction for future developments (2–4).

Experimentally Validated Thermo-Mechanically Coupled FE Simulations of Al/Mg Friction Stir Welded Joints

2013 ◽  
Author(s):  
A. H. Kheireddine ◽  
A. H. Ammouri ◽  
G. T. Kridli ◽  
R. F. Hamade
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Flow Patterns ◽  
Fe Model ◽  
Friction Stir ◽  
Flow Mixing ◽  
Dissimilar Friction Stir Welding ◽  
Daunting Task ◽  
Simulated Temperature ◽  
Deform 3D

Numerical simulations of the friction stir welding of dissimilar metal joints is a daunting task given the complex issues involved such as the flow mixing action and the phase transformations. In this work, a 3D thermo-mechanical FE model is developed to simulate the dissimilar friction stir welding (DFSW) of aluminum-magnesium bi-metallic joints. The model is built using a manufacturing-processing-specific FEM software package (DEFORM 3D). Suitable constitutive laws are implemented to describe flow stress for both welded constituents: Al and Mg. The flow patterns of the stirring action from the simulations were verified against flow patterns of steel shots reported from experiments published in the literature. Also, the simulated interface patterns were found to be in agreement with microscopic images of welded sections taken from reported experiments. Furthermore, simulated temperature profiles favorably compare with temperature measurements previously published in the literature. The numerical model output includes relevant results such as material flow and volume fractions throughout the joint but most importantly in the recrystallized stir zone.

scholarly journals Study on Size-Related Product Quality of Multiscale Central-Punched Cups Fabricated by Compound Forming Directly Using Brass Sheet

2022 ◽  
Author(s):  
Dien Hu ◽  
Jun-Yuan Zheng ◽  
M. W. Fu
Keyword(s):  
Grain Size ◽  
Deep Drawing ◽  
Material Flow ◽  
Dimensional Accuracy ◽  
Thickness Variation ◽  
Forming Process ◽  
Ultimate Deformation ◽  
Physical Experiments ◽  
Deformation Behaviors ◽  
Brass Sheet

Abstract Meso/microforming has gained much more attention in the last decades and is widely used as a reliable method to fabricate meso/micro-scaled metallic components. In this research, a compound meso/microforming system which combines deep drawing, punching and blanking operations was developed to fabricate multiscale central-punched cups by using brass sheets. The parts with three scales were produced by using the brass sheets with various thicknesses and grain sizes to investigate geometrical and grain size effects on the deformation behaviors, dimensional accuracy, and material flow behaviors in the forming process. Through physical experiments and finite element simulations, it is revealed that the ultimate deformation load in the drawing-punching stage is smaller than that in the single deep drawing stage under microscale, but the results in the meso-scaled scenarios are opposite. In addition, the thickness variation is increased with grain size, but the variation of the normalized thickness variation does not show an obvious tendency with different size scales. In the bending area, the material flow is tangential to the thickness direction, leading to the formation of thinning area. In addition, the material flow is almost opposite to the punching direction in the punching area, avoiding the expanding deformation of the hole. Thus, the punching operation barely affects the dimensional accuracy including the thickness and hole diameter of the formed parts. Furthermore, the micro-scaled cups with finer grains have a better surface quality. These findings enhance the understanding of size effect in compound meso/microforming with the combined deep drawing and punching operations.

Sign in / Sign up

Export Citation Format

Share Document